


Irresistible

by PurpleFlyingBird



Category: Merlin (TV)
Genre: Alternate Universe - Vampire, Animal Transformation, Arthur Pendragon Is King, Banter, Blood Drinking, Canon Era, Cross-Posted on FanFiction.Net, Gen, Halloween, Reveal, Samhain, Vampire Bites, Vampire Merlin, Vampires
Language: English
Status: Completed
Published: 2017-12-19
Updated: 2017-12-19
Packaged: 2019-02-17 00:29:07
Rating: Teen And Up Audiences
Warnings: No Archive Warnings Apply
Chapters: 4
Words: 8,112
Publisher: archiveofourown.org
Story URL: https://archiveofourown.org/works/13065369
Author URL: https://archiveofourown.org/users/PurpleFlyingBird/pseuds/PurpleFlyingBird
Summary: Vampire AU. Vampire!Merlin. It is three days until Samhain and Merlin finds himself struggling to protect Arthur from his increasing thirst for blood. As usual, Arthur isn't making his life any easier. Four-shot! Halloween Special! Complete.





	1. Three days left...

**Author's Note:**

> Disclaimer: I do not own Merlin.
> 
> I DO own the image, I drew it myself.
> 
> This story has been posted on Fanfiction.net and I have decided to post it here too. When I originally posted it on Fanfiction.net, each chapter was posted to the corresponding days (Chapter one was posted three days from Halloween 2017, etc). Obviously, I've decided to post it all in one go for this website but for the ultimate reading experience, read Chapter one on the 28th of October, Chapter two on the 29th, Chapter three on the 30th and Chapter four on the 31st (Halloween/Samhain).
> 
> Please enjoy!

**Summary for the Chapter:**

> There are three days until Samhain.

**Notes for the Chapter:**

> "Temptation is the feeling we get when encountered by an opportunity to do what we innately know we shouldn't," –Steve Maraboli

Three days until Samhain. The day which marks the beginning of winter and the darker half of the year. A day of great magical significance to those of the Old Religion. It was also a day when vampires are most active, when their thirst for blood is at its very peak.

Vampires like Merlin.

Unlike many vampires, who are created when a human is involved in a blood ritual performed with an existing vampire, Merlin was a vampire by birth. Just like how he was born with his magic as a warlock. It was because of this that made Samhain a particularly troublesome time of the year for Merlin, as it influenced him more than any other vampire.

Every year, vampires infiltrate the citadel and attempt to attack the sleeping citizens inside, only to be confronted by Merlin.

"Let us pass, Emrys!" The leader of the coven hissed, baring his fangs at Merlin.

"Why should I?" He replied, eying them warily.

"You're a vampire too, are you not? You, Emrys, are our kin," thinking he has won the argument, a smug smile crept over the man's face.

"That may be true. It is nearly Samhain and we all know what that means for us…" Merlin trailed off, a serious gleam in his eye. He added, "More blood is needed to satisfy us."

The vampire leader raised an unimpressed eyebrow, "Yes. So?"

"If I let you pass, then you will attack many innocent people in the citadel and many would be drained until they are dry. Leave now and I won't have to harm you," Merlin's voice lowered, his tone dangerous as he spoke. " _ **No one**_ is passing."

"Very well, if you won't let us pass then we shall have to do this the hard way. Say your good-byes, Emrys," the leader of the coven snarled, his irises flashing crimson, glowing red orbs in the inky shadows of the passageway.

" _Bite me!"_ Merlin taunted, cheekily. The effect was instantaneous, the air was filled with venomous hisses causing the passageway to sound like a pit of livid snakes. A second passed before the first move was made as a vampire charged forward and narrowly missed Merlin's head with their dagger.

Inside him, Merlin felt the heat of his magic rush to the surface of his skin and gather at his fingertips. He raised his hand, holding it outstretched towards the coven and his eyes flared with an almost blinding golden glow that briefly lit up the unrelenting darkness around them.

_No one is going to be drinking Arthur's blood tonight._

* * *

"Rise and Shine!" Merlin chirped as he opened the Pendragon red curtains with a flourish, allowing the early morning sunlight to beam upon Arthur's slumbering face. Having been brought up hiding what he was, Merlin had long since gained a unique immunity to sunlight, allowing him to spend many hours in it with only minor side-effects such as headaches. Although Merlin was once as nocturnal as the rest of his kin, becoming Arthur's manservant had converted him into a morning person-survival instincts helping him adapt to the diurnal way of life that humans live.

" _Merlin_ ," grumbled King Arthur as his manservant yanked the covers off of him, exposing him to the sun's bright rays. Instead of getting up like he was supposed to, the sleepy King buried his face into his soft pillows to shield his eyes, his body curling defensively as though to protect himself from the sunlight as if was he was the vampire and not Merlin.

"Arthur, get up, you've got a busy day ahead. There's training with the knights, a council meeting before lunch, and audiences with the public in the afternoon as well as…preparations for Samhain to begin," Merlin listed as he dragged his friend out of the warmth of the royal bed and, once Merlin had swiftly put a shirt on Arthur, to the table where his breakfast was awaiting him. Merlin's only response was a groan.

While Arthur ate, Merlin busied himself with gathering the laundry for the day and making the bed, tripping at least twice every minute. After Merlin had accidentally knocked one of Arthur's vases over, the King spoke up, concern hidden in his voice which only Merlin could pick up on. " _Mer_ lin. Did you drink too much at the tavern yesterday? You're clumsier than usual!"

"No, I'm fine, Arthur," why wasn't he surprised that Gaius had used the tavern excuse _again_ , even though Merlin had specifically stressed _not_ to? Arthur looked as though he didn't believe him, his blue eyes taking in the sight of the dark circles beneath Merlin's tired eyes.

"You spent all night in the tavern again, didn't you?" Arthur's words coming out sounding more like a statement than a question. The King carried on, not giving his servant the opportunity to deny the accusation, "You know, _Mer_ lin, I'm not the only one who is going to have a busy schedule today."

"Prat," Merlin muttered, giving Arthur a glare which had no effect on him other than causing the King's smirk to widen in amusement.

"My chambers need tidying, the floors need scrubbing, my sword and armour need polishing, my dogs need walking, _and_ …" Arthur trailed off, a gleeful twinkle in his sea blue eyes. Merlin knew Arthur too well to know what dreaded words would leave his royal lips next and he wasn't wrong. "The stables need mucking out."

"My _favourite_ chore," Merlin drawled sarcastically and Arthur rolled his eyes, smirking.

"Then you wouldn't have a problem doing it then? Would you, _Mer_ lin?" Arthur jibed.

"The same way you wouldn't have a problem listening to the council drone on about the number of grains, _Sire_?" Merlin retorted.

" _Merlin._ "

"Shut up?"

"You guessed it," said Arthur as he stood and moved behind the screen to remove his nightclothes while Merlin picked out an outfit from the wardrobe. "The red shirt today, Merlin."

"Yes, _Sire_."

Dressing Arthur that day turned out to be easier said than done. Merlin carefully slipped the high-quality silk shirt over Arthur's head and found himself standing very close to Arthur's neck, his breath ghosting over the exposed skin. Arthur shivered slightly but didn't back away since he wasn't completely dressed yet, instead he stood still as he waited for Merlin to finish dressing him.

" _Mer_ lin. I haven't got all day. Busy schedule, remember?" Arthur's annoyed voice snapped Merlin out of his thoughts of what it would feel like to sink his fangs into Arthur's neck.

"Sorry, _Sire_ ," Merlin replied, distractedly, as he fought to tear his eyes from where they had locked onto a rather delicious-looking section of Arthur's neck and hastily finished the task. Eager to escape before he could do something he would regret, Merlin hurriedly excused himself: "If that would be all, Sire. Gaius told me that he needed some more herbs today, can I…?"

"Go on then. Don't forget to muck out the stables!" Arthur called to Merlin's rapidly retreating figure.

Luckily for Merlin, the rest of the day passed without as much as a single problem. If mucking out _all_ of the royal stables don't count as a problem, that is.


	2. Two days left...

**Summary for the Chapter:**

> There are two days left until Samhain.  
> Arthur and Merlin go on a hunting trip.

"Arthur, my feet are numb, can't we go back now? Don't you think we've had enough hunting for today?" Merlin complained, dragging his feet behind his King. Arthur huffed and rolled his eyes.

" _Mer_ lin, we have only been out here for two hours and we _still_ haven't caught anything. Whose fault do you think that is?"

"Mine? Because it's always Merlin's fault, 'Merlin, it's your fault that I missed the hare,' or 'it's your fault, _Mer_ lin, that those bandits found us.' _Why is it always Merlin's fault?!_ _I didn't do anything!"_ ranted Arthur's manservant.

"Last time, you coughed and ruined my aim," Arthur recounted, daring Merlin to deny it.

"There was a lot of dust in the air where we were crouching!" Insisted Merlin, his arms waving wildly in a vague gesture meaning to symbolise the supposed 'dust' responsible.

"Dust," Arthur deadpanned, raising an eyebrow in a manner eerily similar to Gaius.

"Yes! Dust! The dirt is very dry there and you were kicking it up when you were rolling around behind the bushes!"

"I was _not_ 'rolling around'! I was keeping low to the ground so that I wasn't seen by the deer," Arthur countered, indignantly, because Kings _do not_ 'roll around' when hunting.

Merlin opened his mouth to claim otherwise and that was when Arthur saw him.

A majestic hart* with the largest set of antlers Arthur has ever seen, was standing amongst the trees a couple of paces away from them. His ears swivelling around at the slightest rustling of leaves in the chilly autumn breeze. Arthur promptly clapped a gloved hand over Merlin's mouth to prevent his servant from ruining the once-in-a-lifetime opportunity.

"Don't. Say. A. Word. Got it?" Arthur whispered sternly into Merlin's ear. When his servant nodded, Arthur removed his hand and carefully took his crossbow from Merlin. He was so focused on aiming the weapon at the handsome hart that he missed the strange hungry look Merlin had given his hand.

The expression on the vampire's face changed into a look of awe once Merlin turned to see the poor innocent animal that Arthur was going to kill. What a _beautiful_ animal! Merlin couldn't prevent the gasp from escaping his mouth at the sight of such a magnificent mammal. The sound of the sharp intake of breath the servant had made caused the hart to lift his head in their direction, both ears pricked towards them. King and servant stared back at the hart until the moment was over and the deer bounded away.

"You _complete_ _ **idiot!**_ Why do you _always_ have to open your big mouth?!" Snapped Arthur as he whirled on his manservant.

"I…he…did you see how beautiful he was? I couldn't… I didn't mean to…I…" Merlin stammered, scrabbling backwards away from Arthur who was stalking towards him, fuming.

"Shut up, _Merlin_ and _get up_. We are _not_ going back to Camelot until we have got that hart. Do you understand?"

"Yes, _My Lord_ , I understand," Merlin half-replied, half-groaned in reply before trailing behind Arthur as he led the way.

After several hours of tracking the prized hart with little luck and only a few signs to follow, the sun began sinking beneath the horizon plunging the forest into the darkness of dusk. Above them the thick canopies of the trees blotted out the light of the moon and stars, leaving them to stumble through the blackness. _(Well, Arthur stumbled because he couldn't see. Not Merlin-he's a vampire. Merlin could see perfectly fine at night, thank you very much. He was just clumsy, that's all)._

Following the hart had led the pair of them far up to the north, where winter's fingers had already touched, leaving the earth frosty beneath their feet and the air chilly with winter's breath. "Let's set up camp here. We shall search for the hart on the morrow," Arthur declared and Merlin released a very visible relieved sigh before doing his job. As they settled down for the night in their bedrolls, the temperature dropped to a body-numbing, teeth chattering level of freezing.

"I think I'm missing a toe," Arthur commented as he shuffled closer to Merlin so that they laid side-by-side on their bedrolls. The contact with their sides giving them little warmth, only the comfort of their companionship, yet it was still better than nothing.

"I'm missing Camelot. Missing my food. Missing my bed…" replied Merlin as he shivered, his threadbare clothes and thin blanket doing nothing to keep the cold at bay.

" _Mer_ lin."

"Yes, _Sire?"_

"Shut up and go to sleep," the silence remained for a moment, with only the sound of Merlin's quivering breaths to fill it, loud in the hushed forest.

It was broken with Arthur's voice, _"Merlin."_

"Huh?"

"You're breathing."

"Sorry," Merlin's apology was quiet as he struggled to fall asleep with Arthur's side pressed against his and with the cold clawing at his skin. Although the chilling temperature had done well to distract Merlin during the day, now when Arthur was vulnerable and close enough that they were somewhat half-huddling _(not cuddling!)_ for warmth, it wasn't doing so well at keeping his thoughts of blood away.

Merlin listened to the sound of Arthur's heart beating, alive and well. Normally, it was a comforting sound that reminded him that his best friend, someone he considered a brother in all but blood, was safe. Now, it was an enticing beat that beckoned him closer. It flooded his mind with lustful thoughts of drinking blood. How much he would love to sink his fangs into that neck and taste Arthur's blood on his tongue. To feel that rush of satisfaction as his hunger is sated…to drink until-no he wouldn't.

Not Arthur.

The impulses and thoughts that he experiences during the time around Samhain scare him sometimes. If he wasn't careful, if he couldn't resist the temptation to bite Arthur and drink his blood…then Arthur…

 _If he couldn't stop drinking Arthur's blood…_ the thought was too painful for Merlin to finish.

Not to mention, for that to happen Arthur would have to discover that Merlin is a vampire and what would happen to their friendship? Would Arthur be scared of him? Would he be angry or disgusted? Or would he accept him? Why would he? Surely Arthur had been told that vampires were just as evil as sorcerers?

Merlin would just have to protect Arthur from himself. He can't hide himself somewhere far away from Arthur until Samhain was over because the other vampires would take that as an opportunity to drain Arthur's lifeblood for themselves.

No…he would just have to be careful and think about other things like:

' _It's so COLD! Why for the love of Camelot did that clotpole, prat, turnip-headed ASS have to follow that poor hart to such a horribly freezing place?!'_

**Notes for the Chapter:**

> *Hart is an archaic word for "stag" from Old English. In medieval times, the male of a red deer is a hart especially if over five years old (and the female is a hind, especially if three or more years old).


	3. One day left...

**Summary for the Chapter:**

> There is one day left until Samhain.  
> Merlin struggles with his increasing thirst for blood.

Merlin and Arthur arrived back in Camelot the next day, after having spent it in a forest up north while hunting. During the early hours of the morning, the King had finally managed to shoot the prized hart he was tracking and so they both returned to Camelot in time for Arthur's morning training.

"Aren't you tired? Why is it that the moment we get back you want to swing a sword around?" Merlin grumbled as he dressed Arthur in his chainmail while carefully avoiding staring too long at his King's neck. Instead, he kept sending the tantalising flesh small glances, Merlin could feel his resistance crumbling with every hour that passed as Samhain approached.

"I'm not _tired_ , Merlin. As a knight, training every day is very important, otherwise we may become too out of practice. You remember what happened to Sir Dornor?" Asked Arthur as Merlin began placing his armour on him.

"Yes, didn't he get his finger sliced off during a bandit attack? I remember how Gaius sent me to go and search for it," Merlin recalled, grimacing at the memories that resurfaced of Sir Dornor's lost finger.

"That was because he didn't go to the morning practice for two weeks before the attack and it showed when he couldn't parry the blow fast enough. He learned that lesson the hard way and lost a finger from his sword hand," Arthur confirmed, once he was fully dressed-complete with his sword Excalibur-he continued, "let's go before the knights start to wonder what has happened to us."

* * *

Arthur parried Sir Leon's sword before performing an elaborate manoeuvre that left Leon open to attack. Merlin watched from the side lines as Arthur swung his practice sword in a sweeping arc that finished in the perfect position to run the knight through the heart, had the fight been a real one.

The King gave Leon a friendly punch on the shoulder as he congratulated him, "Well done, Leon."

"Thank you, Sire," Sir Leon respectfully replied, smiling cheerfully at the praise.

"Percival, you're with me next. Ready?" Arthur ordered and the two of them got into their battle stances. "Go."

The spar between King and knight went well for several minutes, but just when Arthur was about to finish it, something red flashed in the corner of Arthur's eyes. He felt a shiver crawl up his spine making him feel as though he were a deer caught in the sight of a ravenous wolf. Arthur's moment of distraction only lasted a single second, however, in battle one second is all that is needed to get killed by the enemy. Percival's blade nicked Arthur's cheek as he swerved to avoid the sword heading towards his face.

Although the blades they used during training had been blunt to avoid serious harm, they were still able to draw blood if enough force is used. From the cut on Arthur's cheek, blood oozed from the shallow wound and dribbled down the side of his face. Percival, horrified, apologised profusely as Merlin jerkily rushed over.

"Arthur, you need to go to Gaius now to treat that," advised Merlin, his blue eyes fixed on Arthur's chest.

"Merlin, it's just a scratch, I'll be fine," reassured Arthur, confused at Merlin for avoiding eye contact with him. Merlin almost always looks him in the eyes, it's what made him so different to the other servants in Camelot.

"If you don't get something on that soon, it will scar and we all know how much you love looking at yourself in the mirror," joked his manservant as his eyes wondered to someplace over one of Arthur's shoulders.

" _Mer_ lin," _why aren't you looking at me? What's wrong?_ Arthur thought as he observed his friend's stiff posture.

"Merlin's right, Princess. You should go to Gaius, it would be a tragedy if the Princess' face is scarred," Gwaine interjected, slinging an arm around Merlin's thin shoulders. The servant instantly attempted to squirm away, an odd expression present on his face.

"Fine," Arthur conceded before turning to the rest of his knights and loudly ordering, "Keep sparring, I don't want to come back to see you all lazing around," the King turned to his manservant and added in a softer voice, "Merlin, let's go."

"Oh! Uh…I…Arthur-" Merlin coughed and cleared his throat, his voice sounded hoarse.

"Are you feeling unwell? You sound like you swallowed a frog," Arthur asked, worry hidden in his tone.

"No! Er…yes! Actually, Gaius said I was coming down with a cold and that I should make sure that I get lots of rest. So, I'll just…go…see you, Sire!" Stammered Merlin as he backed away from the baffled knights. The warlock fled the training grounds and didn't stop sprinting until he reached the stables.

Merlin dashed into one of the unoccupied stalls, locking it behind him before sliding down a wooden wall, panting heavily. The vampire lifted a hand to claw at his parched throat. He could still smell the scent of Arthur's blood and he gulped, his throat clicking. Any longer in the presence of an open wound, no matter how small, would have greatly tested his already straining self-control.

 _Maybe Gaius might have something to help him?_ If Merlin remembered correctly, there should be some animal blood in the cupboard that he could drink, but he can't go there now when Arthur would be there!

Merlin moaned. He would just have to wait until it was safe for him to walk through the citadel without attacking someone.

* * *

The rest of the day passed by without anyone getting bitten by a certain skinny, dark-haired vampire- thanks to Gaius' stored cattle blood. True, it wasn't as satisfying or appealing to the vampire, but it helped Merlin squash any unwanted urges until night arrived.

 _Perhaps he should go and call Kilgharrah to see if he can help him?_ Not that the cryptic dragon would be of any help. Merlin still remembered the last time he had asked the ancient fire-breathing reptile what he should do about his vampire issue. Let's just say it wasn't a very informative meeting, as usual.

It wouldn't hurt to try again.

So, Merlin opened his tiny bedroom window and stood as his eyes flashed crimson instead of gold. His body twisted and shrunk, his hands and arms morphing into velvety black wings as black fur erupted over his skin. His ears became longer and more mobile while his feet became pointed claws.

With a sharp squeak, Merlin in his bat form took off into the cool night air and soared high towards the twinkling stars. The view of the citadel was as breath-taking as always and Merlin had to keep reminding himself to flap his wings as he swooped over Camelot's familiar buildings.

"Arthur Pendragon. His blood…ohhh…it smells so delicious! So good!" A sibilant voice hissed from somewhere in the citadel below, his hyper-sensitive bat ears easily picking up on the sound despite the distance.

A vampire!

It sounded like it was coming from Arthur's chambers. Merlin banked to the left before tucking his wings flat against his body as he entered into a dive. The wind whipping at his small body, threatening to push him out of the steep dive and send him spiralling into the hard courtyard below. Instead, Merlin skillfully pulled out of the dive and swooped into Arthur's open window. He flitted briefly about the room, noting that the King was still asleep with the vampire looming over him, before landing in the shadows across the room.

When the intruder blinked, a servant boy stood where the bat had landed, crimson eyes glaring in the darkness. "I won't let you hurt Arthur," the voice was confidant yet barely a whisper, his tone imbued with a deadly promise.

Before Arthur's would-be-attacker could say otherwise, the crimson pools swirled into molten gold causing a powerful unseen force that defenestrated* the vampire-leaving it with no other choice but to transform into a bat to avoid falling to their death.

With the attacker gone and Arthur safe, Merlin turned to leave Arthur's chambers when a voice spoke up from nearby. " _Mer_ lin? _What_ in the name of Camelot are you _doing?"_

Panicking, Merlin's mind leaped into overdrive, trying to come up with a good excuse. "Checking for ants on the windowsill."

"Ants? At this time of night?" Arthur asked, his voice sceptical yet still rough from being woken late at night.

"Yes, they like to come in during the night through the window to search your chambers for food," Merlin rapidly explained as he approached Arthur to see him sitting up in bed, hair dishevelled and blue eyes hazy with sleep. Arthur looked back at Merlin, unconvinced. "They're very sneaky. Ants."

"Right…" Arthur drawled, ending the word with a tired yawn. "Just go to bed, Merlin, before I decide that you should start Samhain with a trip to the stocks."

Samhain…the day when his thirst for blood would be at its peak.

As Merlin curled up in his bed in his room, he hoped that tomorrow he would be able to resist every temptation that would find him.

_He hopes that Arthur would stay safe._

**Notes for the Chapter:**

> *Defenestration is the act of throwing someone or something out of a window.


	4. Samhain has arrived.

**Summary for the Chapter:**

> Samhain has arrived and Merlin's desire for blood is at its peak. Will he be able to resist the urge to quench his thirst for blood?

"Samhain...It is the time of year when we feel closest to the spirits of our ancestors. It is the time to remember those that we have lost…to celebrate their passing," Arthur Pendragon's speech rang clearly through the dining hall, the knights, servants and nobles listening to their King's every word. It was the same speech that Merlin had written for Arthur and somehow, when those same words flowed from Arthur's lips, so passionately-they became something much more. Merlin could see the great King that his friend had become and it filled him with pride. "To our ancestors!"

"To our ancestors!" The audience echoed, raising their goblets up high in a toast to the spirits. Gwaine lifted his goblet up so fast that half of the red wine inside got sloshed over the rim. The sight of it was so similar to the blood Merlin craved that the vampire felt his thirst for it drastically increase. He felt a wave of dizziness wash over him as something twisted painfully in his stomach. His fangs threatened to lengthen without his say while a red haze crept around the edges of his vision.

Blood…

It was unlike anything he had experienced during the past few days, the need to bite _something_ was all too much. Merlin's throat felt dry, making swallowing a painful experience and he just _knew_ that no liquid but _human blood_ could make it all go away.

_Blood…_

No he couldn't…Arthur would…

As much as he had to leave before he would do something he would regret, Merlin still needed to be there at the feast to serve Arthur. Merlin shifted the pitcher of watered wine into a more comfortable position as he waited for Arthur's cup to empty. The longer he stood the harder Merlin found it to concentrate on serving. His unfocused gaze drifted from Arthur's goblet on the table to the pitcher in his hands and the liquid inside it. He watched as the swirling wine morphed into a thicker, more viscous scarlet liquid.

_**Blood…** _

A hand landed on one of Merlin's shoulders and he flinched, jolting him out of his stupor. Merlin looked over his shoulder to see Gaius standing behind him, concern written across his weathered face. The wrinkled hand steered him away from the table where the feast was taking place, his mind distantly registering Gaius' voice and Arthur's as he excused them. As they walked, Merlin felt as though his mind was detached from his body, his feet moving without him feeling them.

At some point, Merlin wasn't sure when, his foggy mind recognised that the two of them had made it back to Gaius' chambers. Merlin felt something cold pressing against his lips accompanied by a distant clink of something else-something solid-which had bumped against the object _(his fangs?)_. A sweet scent entered his nose, something that he desired?

 _Blood? Not human blood…_ A sense of disappointment lurched inside him, clawing wrathfully at the back of his throat.

"Human…blood…urgh…" Merlin rasped, someone's hand entered his vision and pushed the goblet away from his lips. Seconds later, it clicked in his mind like a missing puzzle piece that the hand he had saw belonged to him.

"No, Merlin, you cannot have any while you are like this. Drink this, it would help," a familiar voice instructed from somewhere beside him.

"But 'S not human blood…" he growled. Crimson eyes flicking towards the source of the nearby voice where a fuzzy, vaguely human blur resided, "You're human…why not give me…yours?" Merlin titled his head, eyes lingering on the old man's neck.

"Merlin!" The voice admonished. "You are not yourself! If I let you have my blood you would come to regret it later once you have returned to your senses."

"Regret it? But I'm so… _so_ _ **thirsty**_ ," groused Merlin, smacking his lips.

"Oh my boy…I know," the voice replied as the goblet returned to its place under his nose. "Drink," and Merlin reluctantly did as he was told. The instant the animal blood flushed into his mouth, the fog cleared from Merlin's mind as his eyes focused on Gaius' worried face.

"Oh. Gaius…I-" Merlin coughed before starting again, "You were right…Gaius. I'm sorry that I tried to… tried to…"

"It's all right, my boy, I understand," reassured Gaius, he patted Merlin's arm.

"Thanks for…you know," Merlin said, gesturing to himself and the goblet of animal blood.

"You're welcome, Merlin," Gaius replied, smiling gently.

"What about the feast? Has it finished yet?" Merlin questioned, suddenly remembering their abrupt departure from it.

"No, not yet. You were only gone for half an hour," Gaius answered and one of his dreaded eyebrows began climbing his forehead, "why? You're not going back are you? I'm sure Arthur can survive being served by someone else for a few more hours. It's still Samhain, Merlin, and the hour when your desire for blood will be at its peak has not yet passed. If you go back now, you would most certainly bite someone."

"I know…Gaius I…I'll stay here for now and wait until it's over. I still need to go and prepare Arthur for bed once it is finished," said Merlin, wearily. He sighed, stood up and headed towards his own small chambers up the short staircase.

"Merlin…" Gaius called to the retreating vampire.

"Yes?"

"Be careful."

"Aren't I always?" Merlin joked, sending his mentor a weak smile before entering his room and closing the door.

* * *

When Merlin woke from his slumber, the unbearable thirst had returned. He knew the animal blood wouldn't help with ridding him of it, but at least-for now-his head was clear again.

Groaning, he got up and trudged down the familiar path to Arthur's chambers. The feast should be nearly finished and his King could leave the hall at any minute now. Arthur's royal chambers were empty when Merlin arrived. Dragging his feet towards the wardrobe, the magical servant removed Arthur's nightclothes and laid them on the large four-poster bed. As he did so, his eyes locked onto the bed's covers.

_Pendragon red covers…_

_Blood red covers._

Arthur's chambers were decorated liberally with the mouth-watering colour. Its vibrant hues bathing the room in blood _-delicious blood-_ red. Merlin's vision blurred as the red haze crept back into sight, he staggered and gripped onto the back of a chair, hard, to steady himself. Something sharp was raking the inside of his throat raw, like a set of jagged daggers slicing through his skin: it was his _thirst for human blood._ Tearing at him like a starved cat, desperate to escape, to be released.

_He shouldn't!_

_He mustn't!_

_Don't!_

_**Click!**_ The door to Arthur's chambers swung open with an ominous creak and the King himself stumbled inside. Merlin hurriedly flung an arm over his eyes, he could still _feel_ them burning crimson red with lust for blood.

"Merlin," Arthur's voice pierced through the gathering fog, grounding Merlin momentarily, "don't just stand there. Get over here so that I can go and sleep."

"Yes…Sire," Merlin's replied, hoarsely. He blindly groped for the clothes he had laid out on the bed and cautiously approached Arthur with one hand still firmly covering his eyes. He didn't need to see to know where Arthur was, he could smell Arthur's enticing scent from across the room.

Merlin soon realised there was a flaw in his plan once he had reached Arthur.

_He can't dress the King one handed! Not without magic!_

" _Mer_ lin. What in the name of Camelot are you doing? You look ridiculous. Stop covering your eyes and dress me," said Arthur, the amusement easily heard in his voice. The King chuckled and Merlin felt a hand ruffling his hair.

"Yes, Arthur," Merlin replied, quietly. He complied and in lieu of his hand, Merlin kept his eyes squeezed shut. Arthur couldn't pass up the opportunity to tease him.

"I understand that I'm very handsome, _Mer_ lin, but you don't have to be so shy. You've done this plenty of times before, don't be such a girl," Arthur commented, smugly.

"Prat…it's not…argh," Merlin muttered, his eyes still shut tight while his stomach lurched. He fumbled around and nearly overbalanced when Arthur moved to one side causing Merlin's hand to miss.

"You idiot. Just open your eyes. Why aren't you opening them?" The hint of suspicion in Arthur's tone sent alarm bells ringing in his head. Then out of no-where a hand cuffed the back of his head, causing Merlin's eyes to blink open from the unexpected contact. From somewhere in front of him, Merlin heard a sharp intake of breath that was followed by a soft whisper. "You're a…"

Puzzled, Merlin tilted his head, blinking slowly as his eyes focused on the astounded expression on Arthur's face. Eventually, the rest of Merlin's mind caught up with him causing his glowing eyes to widen in dawning horror. "You're a _vampire!"_ Arthur exclaimed, shocked. Seeing the brief flicker of fear in Arthur's sky blue eyes was like a knife wrenching deep into his heart.

"Arthur…I…" Merlin stammered, he stumbled backwards in an attempt to put some distance between them, knowing it might help put Arthur at ease again. He tripped, falling backwards onto the floor and continued to shuffle away when he saw Arthur begin closing the distance.

Something solid jabbed into Merlin's spine as he felt the corner of Arthur's wardrobe halt his progress. _"Arthur,"_ he pleaded urgently, not knowing what he was pleading for. Maybe it was a plea for Arthur to forgive him, to understand him? Or maybe it was a plea for his blood? Merlin didn't know. His neck had to bend awkwardly for him to look up at Arthur's figure looming over him as he sat on the floor, trapped between the King and his wardrobe. Their eyes met and Merlin couldn't prevent the shiver that shot across his skin.

Arthur's eyes…for the first time since Merlin had arrived in Camelot, he couldn't read them. Feeling unnerved, Merlin's crimson eyes dropped from Arthur's, breaking their eye contact so that he could lower his head dejectedly. The corners of his eyes burned as his vision lost focus again, however, unlike before it wasn't from the thirst but from unshed tears that caused his sight to blur.

" _Merlin_ ," Arthur's voice snapped sternly from where he stood above him. The vampire refused to look up, he didn't want his nightmares to come true, he didn't want to see the hate in Arthur's eyes. There was a rustling of clothes before Arthur spoke again, his voice much closer than before. This time the King spoke with a surprisingly soft, gentle tone, "Was this why you have been acting strange recently?"

"W-what?" was all Merlin could choke out in response, his eyes flicking up to meet Arthur's before darting away. Arthur was crouching before him so that they were at eye level with each other.

"Yesterday, when I got cut during morning training, you ran off instead of following me to Gaius' chambers. Then during the feast, Gaius escorted you out saying that you were feeling nauseous. Was it because of all-" Arthur made some odd, vague gesture at Merlin, "-this?"

"Yes," Merlin replied, unable to form any coherent thoughts in his mind at Arthur's somewhat calm reaction.

"Why? Did you not have enough blo-" Arthur's sentence remained unfinished as Merlin interrupted him with: "-Don't!"

Arthur raised an eyebrow, silently commanding Merlin to elaborate. After five seconds of the scrutiny, Merlin caved-his shoulders slumping with defeat as the tension left him. "At Samhain, vampires feel the need to…" _feed_ , the word was silently implied, "…more greatly than any other night of the year. It's…it's _unbearable_. Just… _please_ don't say it…I can't…I'm trying not to think about it."

Arthur frowned and stood up before he began to pace around the confines of his chambers. "So you're telling me that you are…you know…and all you're going to do is ignore it? When today is the day that you need to have some the most?" Without warning Arthur spun around to face Merlin, "Why don't you drink some animal blood? Surely Gaius has some for you to drink?"

" _Arthur,"_ groaned Merlin, sending Arthur a withering glare. "He _did_ , after the feast, but it's never…enough…on Samhain…I _need_ … _human blood_ …" Merlin explained through gritted teeth, the action causing his gradually lengthening upper canines to show. Merlin hissed, fangs bared and scarlet irises gleaming, _**"I need…your blood!"**_

Startled at his own words, Merlin stared wide-eyed at Arthur before ducking his head again, frightened and ashamed. "Sorry," he rasped, "I didn't mean to..."

"If you drink my blood, would you feel better?" The question came unexpectedly, breaking the silence that had fallen over them. Arthur strode towards his servant, blocking all of Merlin's escape routes-trapping him.

"No! Arthur!" Merlin yelled, horrified, "I won't…I don't…I don't want to hurt you!"

"Why not? You're a…Merlin you're a _vampire_. Shouldn't you be jumping at the opportunity for offered blood?" Uther had probably filled Arthur's childhood with stories of evil voracious vampires who would attack anyone the instant the opportunity presented itself. Merlin was only thankful that Arthur hadn't drawn his sword the moment he had seen Merlin's glowing eyes.

"Please don't tempt me, Arthur. _I don't want to hurt you_. I'd rather stay thirsty for the rest of my life. Please," Merlin begged as he struggled to resist the temptations presented to him.

" _Mer_ lin…you _need_ it, you even said so yourself," Arthur's voice was soft, touched by how much his friend cares for him.

"I won't…I w-won't bite you," said the vampire, stubbornly. Arthur's hand stretched forward and landed on one of Merlin's knees, the vampire visibly flinched at the sudden contact-the action causing hurt to glimmer in Arthur's eyes. Arthur instantly removed his hand as though burned, it hovered awkwardly in the air for a moment before slowly drifting towards his dagger's sheath on his belt. Merlin's wild eyes followed the movement, watching as the King steadily unsheathed the sharp blade.

Instead of slitting Merlin's throat, the dagger was slowly positioned above Arthur's left hand and, to Merlin's dismay, performed a small incision on his own palm. "W-what are you… _don't_ … _no! Arthur!_ " The effect was instantaneous. His fangs finished lengthening, poking out from underneath his upper lip while his mind returned to its previous hazy state of confusion.

 _No…_ he _needs_ to fight it! He can't lose control of himself again!

Merlin writhed on Arthur's floor, fingers scrabbling urgently at his throat while he fought to keep his mind clear from the red fog. Two hands gripped his shoulders firmly, holding him still and guiding him into an upright position. Merlin blinked as one of those hands was held in front of his face and his eyes immediately zeroed in on the cut. The glistening red blood dripped languidly from the thin wound, its fragrant scent overpowering all the others surrounding him.

_**Blood…human blood…** _

Merlin licked his lips, his tongue gliding along his fangs as he did so, and gulped audibly. "Drink it, Merlin. It's yours. Go on," encouraged Arthur's voice. The hand moved closer, Merlin's glowing eyes trailing it, until the cut was pressing against his mouth, the sweet blood dripping onto his lips.

Tentatively, Merlin's tongue darted out to taste it and was instantly rewarded with the most delectable flavour tingling his taste buds. The vampiristic insatiable hunger spiked inside of him. He latched onto the hand with both of his own, keeping it still as he leaned forward, mouth opening with his fangs bared. Before he bit down, Merlin's ravenous eyes glanced up, meeting Arthur's.

The vibrant blue of his friend's eyes shined brightly through the ever-darkening haze, jerking him back to his senses. _"Arthur!"_ Merlin yelped, hurdling to his feet and stumbling away. He frantically wiped Arthur's blood from his lips onto the sleeve of his blue tunic, staining it with a purple smear. His sharp fangs, which still have not yet retracted, caught on the course fabric in his haste, tearing a small hole in it. "Mmph? Argh!"

Taking advantage of Merlin's distraction with the problem his fangs had caused, Arthur strode towards Merlin and grabbed hold of the man's arms. "Arthur? Wha-" Merlin was cut off as Arthur abruptly pulled him into a tight embrace. Ever since Merlin had been told about the time when Arthur had hugged him while he was under the influence of the Fomorroh, Merlin had pestered Arthur for another hug. However, it is well known that Arthur doesn't do hugs and to receive one from him is as rare as seeing a lunar rainbow.

Merlin froze, shocked as he felt Arthur's arms wrap around him while Arthur's warm breath fanned the back of his neck. The comfort and warmth of his most precious friend enveloped Merlin, soothing his frayed nerves and bubbling guilt. "Merlin, it's okay…calm down," Arthur's voice spoke gently in his ear, "I _want_ you to drink my blood, I _want_ to help you."

As soon as Arthur's words registered in his mind, Merlin began to attempt to wriggle free, pushing at Arthur's chest and desperately trying to pry himself from the arms caging him. "No! I won't! Arthur! Let me go!" He didn't want to taint this new memory with such an awful deed.

" _Mer_ lin, it's not going to be against my will. I've been through worse, getting bitten by a vampire shouldn't hurt too much, right? I'm asking you to do this for yourself, you selfless _idiot-_ " Arthur attempted to console his friend, only to be cut off.

"-I don't know if I can stop, what if I don't and you lose too much?" interrupted Merlin, fretful as he struggled in Arthur's hold.

One of the King's hands moved from Merlin's shoulder blade to the back of Merlin's head. His fingers carding through the soft hair in a comforting gesture as he guided the unsuspecting vampire towards his neck. "As odd as this may sound given everything that I've seen today, I trust that you won't go that far. It's true. _I trust you, Merlin_ , so shut up and _bite me_ ," his last two words unknowingly echoing Merlin's from three days ago.

_Irresistible._

It was the perfect word to describe it. Both the offer and the sight of Arthur's neck so _close_ to his fangs. It was all too _irresistible._

With his final resistance crumbling down, Merlin slumped into Arthur's embrace, his arms tentatively returning the hug and pulling his friend closer. Arthur's heartbeat thudded like a war drum in his sensitive ears, drawing him to the pulsing point on Arthur's neck. As Merlin leaned in, his eyes glowing crimson with his thirst for blood, Arthur tilted his head to the other side in order to give his vampire better ease of access.

_Ba-bump... Ba-bump…Ba-bump…_

Merlin's fangs slowly extended, his eyes fixed hungrily on Arthur's offered neck.

_Ba-bump…Ba-bump…_

He opened his mouth, baring his fangs as he lowered his head. A soft hissing exhale escaped, passing through his lips.

_**Ba-bump…Ba-** _

Arthur stifled a cry as Merlin sank his fangs deep into his neck. The pain was short-lived as the area around the long canines was numbed by the vampire's saliva. Arthur's fingers tightened their grip on his servant's scruffy jacket as his heart pounded in his chest sending his life blood rushing to the puncture wounds on his neck.

* * *

The instant Arthur's warm blood flowed through Merlin's hollow fangs and into his mouth, the vampire felt the constant scratchy dryness in his throat gradually begin to abate. On his tongue, Arthur's blood tasted as heavenly as he had ever imagined it to be. It was as deliciously sweet as it smelled, with the ever present metallic tang that as a vampire, always sent his taste buds tingling. Merlin gulped the mouthful of blood and felt it travel down his once-parched throat and into his stomach, the feeling was unbelievably satisfying.

Eager for more, Merlin's fangs drew more blood into his mouth and after a moment to savour the taste, he swallowed it in order to make room for the next mouthful. His hands grasped at Arthur's expensive jacket, the feeling of fine leather beneath his palms helped to ground him when the red haze of hunger for blood threatened to cloud his mind.

When the twisting in his abdomen settled completely, Merlin _knew_ that he _needed to stop_ _ **now**_ or Arthur would go into hypovolemic shock* or _worse._ He couldn't _bear_ to lose Arthur, his friend, especially not like this. _Not Arthur._

The blood…Arthur's blood tasted _so good_ , he didn't feel like stopping. Just a little more… _more_ … _ **more blood…**_

Merlin felt Arthur's hand patting him on the back, his familiar voice sounding strained, " _Merlin._ That's enough, isn't it? When are you going to stop?" _Stop? Why should he…_ "Merlin! Remember what I told you!" _Remember what?_ Merlin felt like he was forgetting something incredibly important as he drank the warm, blissfully tasty blood. _What did he say? Oh…_

" _I trust that you won't go that far. It's true. I trust you, Merlin."_

_Stop! He_ _**needs** _ _to stop_ _**now!** _

Merlin, as quickly as he was able to, carefully removed his fangs from Arthur's neck. Feeling guilty about what he had done and terrified for Arthur's health, Merlin gently pulled away only for Arthur's legs to give in the moment the only person supporting him had backed away. With quick reflexes, Merlin's arms shot out to catch his dizzy friend, pulling one of Arthur's arms around his shoulder so that his friend could lean on him. Merlin slowly led Arthur over to his bed and tucked the covers around him so that he could rest. After double checking to see if Arthur was all right, Merlin started to leave so that he could fetch Arthur some food when he was stopped by a hand that had caught his wrist.

"Stay," Arthur's voice was weak and quiet, yet Merlin was still able to hear it all the same.

"Arthur, I'm sorry it t-took me a while to s-stop, I…I just…you need some food to help you recover," Merlin's voice shook as he replied, keeping his sorrowful now-blue eyes downcast with shame and gnawing guilt.

"Don't apologise, _idiot_. I asked you to do it. It's not your fault. More importantly do you feel better?"

"Me? How can I feel better when you're lying in your bed because of me?" Merlin choked out. His eyes stung as tears gathered at their corners before creating silvery wet trails down his bony cheeks.

"Merlin…" Blue met blue as Arthur's eyes met Merlin's before the King continued, "How many times do I have to tell you that I wanted you to drink my blood? You didn't hurt me…most of the time it felt numb and now…now it feels really weird," Arthur's nose scrunched as he added, "it's all tingly."

"Tingly?" Merlin asked, a laugh bubbling up through his tears and a small smile quirking his lips. Arthur returned the smile.

"Yes. Now stop blaming yourself for something I asked you to do and answer my question," Arthur commanded.

"Okay, okay… _Prat_ …" Arthur's smile widened into a grin in response, "I don't feel thirsty anymore…that unbearable dryness in my throat is gone and I feel…" Merlin smiled contently as he basked in the feeling that had replaced the insatiable hunger, "…satisfied."

"Good. That's nice to know," said Arthur, pleased. Silence reigned over them as Merlin fiddled nervously with the hem of his tunic's sleeves.

"Do you…do you hate me?" The vampire hesitantly asked.

Arthur drew his eyebrows together, confused. "What?"

"After what I've done? What I am…" Merlin elaborated, anxiously.

After realising what his friend meant, Arthur hastily reassured him, "No! Merlin… _no_. I could _never_ hate you, _Mer_ lin. Even if you are a starving vampire as well as being the worst servant in the five kingdoms."

"Thank you, Arthur," said Merlin, sincerely, a bright goofy smile spreading across his face.

"Anytime, Merlin. Now you can go and fetch me my food, I feel like I could eat a cow!" Arthur moaned, to his chagrin the King's stomach rumbled in agreement making Merlin laugh loudly.

"Would you like it well done, medium done or _rare_ , _Sire_?" His servant teased.

"Medium done, _Mer_ lin, I don't want to see any _blood_ oozing out of it," Arthur responded, smirking.

"Are you sure? You look like you're in need of a very rare steak," jibed Merlin.

"Yes, I'm sure, I'm not a vampire," Arthur retorted.

"Mm. I noticed," Merlin nodded, giving Arthur a pointed look.

"Merlin."

"Yes, _My lord?"_ was the vampire's sarcastic reply.

"Just go and fetch me some food," the King ordered impatiently, shooing his manservant in the direction of the door. Just before his servant exited Arthur's chambers, he turned to call back over his shoulder with a wide smirk and a mischievous twinkle in his blue-grey eyes:

"As you wish, _Your Royal Prat-ness_ , I'll go and fetch you your food and add another hole in your belt," then without giving his friend a chance to respond, Merlin fled from the chambers and took off into the hallway. Arthur's shout echoing after him.

" _MERLIN!"_

**Notes for the Chapter:**

> *"Hypovolemic shock, also known as hemorrhagic shock, is a life-threatening condition that results when you lose more than 20 percent (one-fifth) of your body's blood or fluid supply. This severe fluid loss makes it impossible for the heart to pump a sufficient amount of blood to your body."
> 
> Mild symptoms include those such as: dizziness, nausea, fatigue, headaches and profuse sweating.
> 
> Severe symptoms include: cold/clammy skin, blue lips and fingernails, loss of consciousness, confusion, rapid heart rate and rapid (shallow) breathing, weak pulse, light-headedness and pale skin.

**Author's Note:**

> Thank you for reading! I hope you have enjoyed it! :)
> 
> Please tell me what you think of it.


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